Cycling shorts issue - any thoughts?

[GLC1968]

Do the welts look like swollen bites...some quite large in surface area? Is it hot where you are/ride?

I also have big legs compared to the rest of me, and I also get what I am assuming are the same welts. They were red and ugly and they didn't go away for a few days. And, mine were both below and above the short line as well. For me, it didn't matter which shorts I wore...I normally wear PI Ultrasensors, but I got the welts wearing Shebeest and Terry, too. And I did try turning up the elastic, and that didn't help.

Come to find out, for me, it was related to heat. It was a weird form of heat rash that manifested itself only on the tops of my thighs. It didn't itch or burn or hurt...it was just ugly (and when it was at it's worst, the surface felt somewhat hot to the touch). I paid extra close attention one day and I could feel them starting. My whole body was begining to 'wilt' and when I looked down, sure enough...they were just appearing. I've found that the only way I can keep them at bay is by keeping my core temp down. Dumping water on my head, wearing a water soaked buff, trying to avoid riding at mid-day...etc. I haven't had them yet this year, but we haven't hit the worst of the summer heat yet either.

Oh, and they only appeared on long rides (greater than about 55 miles) I think because 1) it takes my body that long to get to the 'overheating' temps and 2) the longer our rides, the later in the day I was riding (and the hotter it was).

You may have something totally different, but it sure sounds familiar!